Apparatus for setting selection rails in typewriters



I I Oct.20,1 970 H. STAHL ETAL I APPARATUS FOR SETTING SELECTION RAILS IN TYPEWRITERS Filed Jan. 29,- 1968 Patented Oct. 20, 1970 3,535,449 APPARATUS FOR SETTING SELECTION RAILS IN TYPEWRITERS Horst Stahl, Richard Thurner, and Franz Peischl, Munich,

Germany, assignors to Siemens Aktiengesellschaft,

Berlin and Munich, Germany Filed Jan. 29, 1968, Ser. No. 701,364 Claims priority, application Germany, Feb. 2, 1967, 108,134 Int. Cl. H041 17/18 US. Cl. 178-33 Claims ABSTRACT OF THE DISCLOSURE Selection rails are selectively actuated to select a particular type character from a plurality of such type characters in typewriters and other similar data machines. The selection rails have two arms which when separately urged in the same direction move the type bars in opposite diretions. Each selection rail is actuatable by an associated lever which is shiftable into one of two lateral positions, determined by an incoming binary code, for controlling the direction of motion which is conveyed to the selection rails, thereby controlling the selection of the type characters.

BACKGROUND OF THE INVENTION Selection rails by which the type to be printed is selected are components of most data typewriters. Similarly, it is necessary to provide selection rails of a similar nature for ordinary typewriters which in addition to the ordinary manual typing operation are also suited for transcribing the information stored in perforated tapes into a clear text.

Normally, the energy of the incoming information pulses in data processing installations or in typewriters controlled by perforated tapes is not high enough to be able to actuate the selector key, the intermediate levers, and the selection rails in the actuating direction at the necessary high speed. Therefore, it is necessary to operate the selection rails through an auxiliary drive which is controlled by the incoming pulses.

A system has been suggested for the operation of the selection rails through an auxiliary drive which is characterized by the fact that two guided slide bars are cooperatively associated with each of the selection rails. The slide bars operate in opposed directions by an associated cam which selects one or the other of the slide bars depending on the position of an intermediate member.

The above system requires a very small amount of inertia for actuation since only the intermediate members need to be moved by the energy of the incoming pulses, and this can be conveniently accomplished by magnets. Further cam controlled intermediate levers are provided which are selectively locked or released so that they come into alignment with one or the other of the oppositely acting slide bars. The actual energy for the actuation of the selection rails is transmitted thereto by further cams and the previously set intermediate members, if necessary, i.e., when the actuation of a different selection rail is to be made. It is possible with the above described system to achieve high operational speeds and reliability. In each case the selection rails remain in their last position and do not return to a starting position after each setting operation. For this reason the power which is required is slight thereby reducing the wear and operational noises.

However, a prerequisite for the above described system for setting the selection rails is a cam shaft having two cams for each selection rail. This is an undesirable feature since it is preferable to keep the number of cams used to a minimum in that the manufacture of such cams necessarily results in high expenses due to the close tolerances required. Additionally, the maintenance of the cams arranged on one shaft becomes extremely diificult when some of the cams begin to wear and the apparatus may become economically infeasible.

Acordingly, it is an object of the present invention to provide an apparatus for setting the selection rails which combines the advantages of the above device, but can function without the large number of cams arranged on a cam shaft, which could possibly nullify the close manufacturing tolerances of the other members.

Another object of the invention is to provide a driving motion which is evenly transmitted by a single drive cam to selection levers which are controlled by electromagnets.

A still further object of the invention is to provide a drive mechanism wherein the fluctuations in the driving forces which are generated by the drive cam are reduced during the operating cycle by leveling out the acceleration peaks on the actuation of the selection rails and which compensates for tolerances in the dimensions of the various individual mechanisms.

SUMMARY OF THE INVENTION The invention relates to an apparatus for actuating selection rails of typewriters for the selection of type characters associated therewith. A plurality of selection rails are provided having two arms which when separately urged in the same direction move the selection rails in opposite directions. There are a plurality of levers each of which is associated with a selection rail for actuation thereof and the levers are movable into one of two positions in which they are aligned with one or the other of the two arms of the selection rails. The levers are selectively moved into one of the two positions by the binary code operational commands. The levers are then cyclically driven into engagement with their respective selection rails to select a type character.

DRAWING Other objects, advantages and aspects of the invention will become apparent by reference to the following detailed description and drawing thereof, wherein:

In the drawing there is shown a perspective, schematic illustration of the apparatus forming the subject of the instant invention for actuating the type bars in typewriters.

DETAILED DESCRIPTION OF THE INVENTION In the drawing there is shown a cam shaft 1 having a heart cam 2 mounted thereon which drives a lever 3 in an oscillating manner. Connected to the other end of the lever 3 is a frame 5 which is guided for rectilinear motion between guide plates 4, as it is oscillated up and down. Mounted in the frame 5 are actuator members or levers 6 (five are shown) which are shiftable into one of two lateral positions as shown by the arrow and the lever shown in phantom. In their rest position the levers 6 are urged against an elongated limit stop 8 by associated leaf springs 7.

Upon the receipt of an incoming signal in binary coded form, the levers 6 are set in one of their two lateral positions by a plurality of magnets 9, which are joined together as a unit. The magnets 9 are effective to move the slide bars 10, slidably positioned in a frame 19. When the operational stroke is transmitted from the heart cam 2 via the lever 3 to the frame 5, the setting of the levers 6 as determined by the magnets 9, is transmitted by the levers 6 to a plurality of bifurcated or two armed selection rails 11. The other arm is a shift lever 12. It is to be understood that one such selection rail 11 is provided for each of the levers 6, although only one is shown for simplicity. Those levers 6 which are held in their rest position by the leaf springs 7 during the operational stroke shift the selection rails 11 upwardly if the selection rails are not already in that position.

The shift lever 12 which is pivotable about a fixed axis 18 is effective to urge the selection rails 11 in a downward direction when the particular lever 6 associated therewith has been moved to the left by its respective magnet 9. In this manner the selection rails 11 can be moved either upwardly or downwardly by the vertical motion of the lever 6 depending upon lateral position of the lever 6. Alignment of the levers 6 with either the selection rails 11 or the shift lever 12 is aided by notches 16 and 17.

In order to insure that the selection rails 11 is safely brough into its terminal position by the appropriate lever 6, the levers are positioned on pegs 14 which pass through slots 13 on each of the levers 6. The levers 6 are biased by compression springs 15 away from the bottom of the frame 5. As an operational stroke takes place during the raising of the frame 5, the levers 6 initially engage the selection rails 11 or the shift lever 12 in their notches 16 and 17 respectively. In the acceleration phase that follows, the actuator members 6 are moved against the force of the compression springs 15 so that the pegs 14 of the levers 6 lie at the upper end of their respective slots 13. The further transmission of motion to the selection rail then occurs according to the shape of the heart cam 2. In the terminal upper position of the frame 5, the compression springs 15, via the levers 6, urge the corresponding selection rails 11 or shift lever 12 into their terminal position.

This arrangement has the advantage of equalizing the dimensional tolerances between the individual mechanical members, and also attenuates the initial impact of the levers 6 with their respective selection rails 11 or shift lever 12, thereby more slowly accelerating those members. At the same time the selection rails 11 are thereby securely held in their terminal position by the levers 6 and the compression springs 15 so long as the incoming program permits. This avoids inadvertent movement of the selection rails 11 which could lead to scanning errors. During the subsequent downward movement of the frame 5, a new program setting of the levers 6 can be effectuated by the magnets 9.

Various changes of the particular structural design are within the framework of the invention. For example, it is possible to turn or to shift the selection rails axially in appropriate manner during the operational stroke instead of lifting and lowering the selection rails as described above. Furthermore, it is possible to have the magnet 9 act directly on the levers 6 instead of utilizing the slide bars 10. It is also possible to substitute another electromagnetic system which acts in two directions, thereby eliminating the need for the leaf springs 7.

It is to be understood that the invention is not limited to the particular embodiments and features described and shown, but that it comprises any modifications and equivalents within the scope of the appended claims.

We claim:

1. Apparatus for setting selection rails of typewriters wherein operational commands are supplied in a binary code, which comprises:

a plurality of selection rails each having two arms which when separately moved in the same direction move the selection rail in opposite directions;

a plurality of actuator members each of which is associated with a selection rail for setting thereof, said members being movable into one of two positions 4 in which said members are aligned with one or the other of the two arms of said selection rails respectively;

means for selectively moving said members into one of the two positions as determined by the binary code operational commands;

a movable frame connected to said members;

means for cyclically driving said movable frame to urge each of said members into and out of setting engagement with the respective arm of its respective selection rail to move each said rail in one of said opposite directions; and

a plurality of springs, one of which is mounted between said frame and each of said actuator members to transmit the movement of said frame to said actuator members, attenuate said springs enabling relative movement between said frame and said actuator members, said springs further serving to the acceleration of the respective selection rails upon movement thereof by said actuator members and urge through said actuator members the respective selection rails to a terminal set position upon completion of the movement of said frame.

2. Apparatus as recited in claim 1 which further comprises:

spring second means associated with each of said actuator members for normally holding said members in one of said two positions; and wherein said moving means comprises:

electromagnetic means associated with each of said members and responsive to the binary code operational commands for moving said members into the other of the two positions.

3. Apparatus as recited in claim 2 which further comprises:

slide bars for connecting said electromagnetic means to said actuator members.

4. Apparatus as recited in claim 1 further comprising stop means to limit the movement of said actuator members relative to said frame toward and away from the respective selection rails, said springs normally urging said actuator members toward said selection rails against said stop means so that acceleration of a selection rail following engagement thereof by a respective actuator member causes said member to move away from said stop means against the forces of the respective spring and upon completion of the movement of the frame, the spring urges the actuator member against said selection rail to hold said rail in a terminal position.

5. Apparatus as recited in claim 4 wherein said stop means comprises a pin and slot connection between each actuator member and said frame.

References Cited UNITED STATES PATENTS 775,237 11/1904 Collins 234-115 1,904,164 4/1933 Morton et al. 178-33 XR 3,133,698 5/1964 Hergert 234-115 3,189,270 6/1965 Seymour et al. 234-115 3,194,494 7/1965 Darwin 235-115 3,285,509 11/1966 Galey et al. 234-115 3,328,802 6/1967 Da Motta 234-115 XR 3,373,857 3/1968 Lapointe 197-14 EDGAR S. BURR, Primary Examiner US. Cl. X.R. 197-17; 234-115 

